All the Perl that's Practical to Extract and Report

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Call/cc requires lots of support from the VM, and if the VM isn't designed for it it'll cripple your performance if it isn't completely impossible. To implement call/cc you either need to allocate all stack frames on the heap (which requires an allocator and garbage collector optimised for very high rates of garbage production) or you need to be able to copy the stack when a continuation is captured. While you can implement heap-allocated activation records on the JVM and.net, it's much slower than using t

They aren't necessary if you have a decent set of control structures built in to your language.

They aren't necessary if you have the precise set of control structures that you really need built into your language. That's slightly different from what you said.

As for the Nickclarkulator's second question, Larry's put in a fair bit of work to make sure that it's possible to host a Perl 6 implementation without exposing continuations. Part of that may have been the desire to get Perl 6 running on the Pe